Attention is paid to effective utilization of biomass energy as a preventive measure for global warming. Among biomass energy, since biomass energy derived from plants can effectively use hydrocarbon converted from carbon dioxide by photosynthesis during the growth process of plants, it has a property which is the so-called carbon neutrality and does not contribute to an increase in carbon dioxide in the atmosphere from the viewpoint of the life cycle.
The utilization of such biomass energy has been widely studied even in the field of a transportation fuel. For example, if a fuel derived from an animal or vegetable oil can be used as a diesel fuel, it is expected to play an important role in the reduction of carbon dioxide emission by the synergistic effect with the high energy efficiency of a diesel engine. As a diesel fuel using an animal or vegetable oil, a fatty acid methyl ester oil is known. The fatty acid methyl ester oil is manufactured by subjecting a triglyceride, which is a general structure of an animal or vegetable oil, to ester exchange with methanol by a basic catalyst or the like.
However, as described in Patent Document 1, it is pointed out that the process for manufacturing the fatty acid methyl ester oil has problems. For example, a by-product glycerin is required to be treated and cost and energy are required for cleaning of a product oil, or the like.
In order to use an oil and fat component derived from an animal or vegetable oil or a fuel manufactured by using the component as a raw material, in addition to the above problems, there are the following problems. Specifically, since an oil and fat component derived from an animal or vegetable oil generally has oxygen atoms in the molecule, there is concern that the oxygen content may adversely affect the engine material, and the oxygen content is difficult to remove to an extremely low concentration. In addition, when mixing the oil and fat component derived from an animal or vegetable oil and a petroleum hydrocarbon fraction and using the mixture, the prior art cannot sufficiently reduce both the oxygen content in the oil and fat component and the sulfur content in a petroleum hydrocarbon fraction.
Consequently, a method of manufacturing a fuel oil comprising a hydrocarbon oil by subjecting a oil and fat component derived from an animal or vegetable oil to deoxygenation by hydrogenation (hydrodeoxygenation) is studied (for example, refer to Patent Document 2 and Patent Document 3).